Arthroplasty procedures, such as a total hip replacement (THR), can require the removal of the femoral head and neck, followed by implantation of an artificial hip stem into a reamed portion of the femoral medullary canal. Some hip arthroplasty procedures call for the use of bone cement to secure the hip stem within the medullary canal. For procedures that call for cement, it is generally undesirable to allow the cements to infiltrate the medullary canal to an uncontrolled depth and volume. As such, a hip arthroplasty procedure may include the step of placing an obstruction within the medullary canal in an attempt to restrict or block the flow of cement.
Cement restrictors, therefore, are often used to create a blockage within the medullary canal to block the flow of the cement into the medullary canal. Various cement restrictors are known in the art. For example, U.S. Pat. Nos. 6,280,477; 6,325,830; 5,997,580; 5,879,403; and 5,849,014 disclose various cement restrictors, the disclosures of which are incorporated by reference herein. Other commercially available cement restrictors include the BIOSTOP G® made and sold by DePuy Orthopaedics, Inc. (Warsaw, Ind.).
As mentioned above, many arthroplasty procedures such as THR, call for the use of bone cement to secure the hip stem within the medullary canal. This bone cement is oftentimes pressurized bone cement. For example, adequate cement pressurization may allow the bone cement to interdigitate into the cancellous bone. This interdigitation may aide in the long-term survival of a cemented hip stem. The bone cement may be pressurized by occluding the femoral canal at the distal end, with a cement restrictor, for example, and at the proximal end with a bone cement pressurizer used in conjunction with a bone cement injection gun.
Various proximal pressure measurement devices may be used which directly measure the pressure of the bone cement in the proximal portion of the bone canal. Such devices are often hard-wired to a visual display device to display the pressure of the bone cement for the surgeon. Other measurement systems, such as empirical measurement systems for measuring the pressure of the bone cement, use capillary type devices to determine the pressurization of the bone cement by how far the bone cement is extruded into the capillary tubes during cement pressurization. Further, known distal cement pressure measurement devices require the surgeon to perforate the cortex of the femur to allow a pressure transducer or capillary type system to sense the pressure of the bone cement at the distal end of the canal.